Page 93 - Building A Succesful Board-Test Strategy

Test Methods 79

Figure 2-20 Custom fixturing for testing a right-angle connector. (Courtesy Agilent

Figure 2-21 The force of the probe is far less than that necessary to close the solder
gap.

2.3.8 Other Access Issues
With bed-of-nails access becoming more difficult, companies often rely more
on functional or cluster testing to verify digital circuitry. Because analog circuits do
not lend themselves easily to that approach, it has become necessary to find a viable
alternative. With an average of two to three analog components on every board
node, every node that defies probing reduces the number of testable components by
that same two or three. Pads have shrunk to only a few mils, and center-to-center